A test device with a tape unit for carrying out blood glucose tests is known in an earlier application WO2004/047642, which is hereby incorporated by reference herein in its entirety. It describes among other things a coaxial arrangement of spools lying laterally next to one another in order to utilize the limited total space available in a hand-held instrument as efficiently as possible. However, in this case the total height of the instrument is determined at least by the double tape width and additional thicknesses of intermediate walls.
On this basis, among the objects of the present invention is to further develop the tape cassette systems known in the prior art and to optimize a tape unit comprising diagnostic test elements and/or lancing elements that are unwound from a first spool and wound onto a second spool, with regard to a compact assembly, as well as to provide such a tape unit for an easy to handle instrument system.